The quote you receive from the vendor mostly covers licences. It rarely covers the following:

• Floor plan digitisation
  Your architectural drawings are not usable floor plans. Someone has to convert them, place every desk, tag attributes like monitors and standing height, and redo it after each office change. Ask who does this work and what a re-draw costs in year two.
• Integration effort
  SSO, calendar sync, HRMS, and access control each need configuration and testing. Your IT team’s hours are real money, even when they don’t appear on an invoice. Calendar sync in particular tends to eat more time than anyone budgets.

• Change management
  Employees don’t adopt booking tools because a tool exists. You need launch comms, training sessions, floor champions, and someone answering questions for the first month. Skip this and you get low adoption, which means unreliable data, which means the business case evaporates.

• Ongoing administration
  Policies change. Teams move. New sites open. Someone owns this permanently, and if the admin interface is clumsy, that someone is spending hours a week rather than minutes.

• The Hardware you forgot
  Lockers, if you’re removing assigned desks. Wayfinding signage. Kiosks or panels, plus their replacement cycle. Also the desks themselves, since shared seating usually needs standardised, docking-station setups rather than personalised ones.

• Data cleanup
  Bad seat inventory in, equals bad utilisation reports out. Most organisations discover their desk count was wrong the moment they try to load it.

• The cost of getting it wrong
  Switching platforms means redoing floor plans, integrations, and change management from scratch. That is the most expensive hidden cost of all, and the reason a cheap licence with weak fundamentals is rarely the cheap option.

Before you sign, get written answers on: what implementation includes, what a floor plan change costs, which integrations are standard versus custom, and what support looks like after go-live.